Field of the Invention
The present invention relates to a laminated ceramic electronic component.
Description of the Related Art
Laminated ceramic electronic components such as laminated ceramic capacitors and laminated ceramic inductors are each generally constituted by a component body of laminate structure and external electrodes provided thereon. The component body has a shape of a roughly rectangular solid defined by the length, width, and height, and the external electrodes are provided on the component body in a manner electrically connecting to the internal electrode layers, coil layers, or other conductor parts inside the component body. These laminated ceramic electronic components are widely used in component mounting boards, boards with built-in components, etc., but given the current state where there is a persistent demand for smaller, thinner versions of these laminated ceramic electronic components, there are concerns regarding the connection reliability of external electrodes with respect to conductor pads and conductor vias.
Japanese Patent No. 5217584 discloses a structure of external electrodes 8a, 8b in light of the aforementioned connection reliability (refer to FIGS. 1 and 2 of the patent). These external electrodes 8a, 8b are such that their extended parts 9a, 9b are formed over the top surfaces of the leader parts 5a, 5b of the laminated ceramic element body 3 through the top surface of the function part 4, and the extended parts 9a, 9b on the top surfaces of the leader parts 5a, 5b are lower than the extended parts 9a, 9b over the function part 4; wrap-around parts 10a, 10b are formed over the end face of the laminated ceramic element body 3 through the surfaces of the extended parts 9a, 9b on the top surfaces of the leader parts 5a, 5b; and metal layers 12a, 12b are formed on the surfaces of these extended parts 9a, 9b and wrap-around parts 10a, 10b.
However, the structure of external electrodes 8a, 8b disclosed in Japanese Patent No. 5217584 allows marked height gaps and undulations to form on the top surfaces of the metal films 12a, 12b due to the forms of the extended parts 9a, 9b and wrap-around parts 10a, 10b that are present underneath them, which makes it difficult to improve the connection reliability with respect to conductor pads and conductor vias. If conductor pads are connected via solder to the top surfaces of the metal films 12a, 12b, for example, there are concerns that the aforementioned marked height gaps and undulations will change the clearances between the top surfaces of the metal films 12a, 12b and the conductor pads, thereby making it easy for the amounts of solder at locations of large clearances to deviate from the amounts of solder at locations of small clearances, leading to connection failures. If conductor vias are connected to the top surfaces of the metal films 12a, 12b, on the other hand, the aforementioned marked height gaps and undulations will reduce the areas that can be used for connection with the conductor vias, which may cause connection failures depending on the position tolerances of the conductor vias.